I know better than to lend him any money.我知道不该把钱借给他.I know better than to do such a thing.我不会糊涂到干出这种事情来.The boy is old enough to know better.这个男孩已经长大知道好歹了....
去买东西而不带钱是很蠢的.It is idiotic to go shopping with no money.人们有时做出愚蠢的事情 -- 真正非常蠢的事情.People sometimes do foolish things -- indeed, very foolish things.再蠢的渔翁也不至于钓青蛙.It is a fond fisher that angles for a frog....